The present invention relates to a control mechanism for controlling an inner tube movable in an outer tube.
A conventional retractable tube assembly generally includes an outer tube and an inner tube which is movably received in the outer tube. A control mechanism is used to position the inner tube relative to the outer tube and can be different types. One of the control mechanism known to applicant is that the inner tube has a positioning piece received therein which is a V-shaped plate and a bead is connected to one of two ends of the V-shaped plate. The outer tube includes a plurality of positioning holes and the bead is engaged with one of them so as to position the inner tube relative to the outer tube. However, the V-shaped plate is difficult to be install in the inner tube and once it is shifted from its desired position, the users are difficult to retrieve it from a long inner tube. Another known arrangement is to receive a positioning piece in a dove-tailed groove defined in an outer surface of the inner tube and may engage with one of the positioning holes in the outer tube. This arrangement involves many machining so as to obtain desired complicated shapes in the inner tube and the mechanism.
The present invention intends to provide a control mechanism connected to a sleeve in which the outer tube and inner tube extend, the mechanism is reliable in operation and the inner tube can be well positioned or released by operating the control mechanism.
The present invention relates to retractable tube assembly which comprises a sleeve having a through hole through which an outer tube and an inner tube extend, and an opening defined through a wall of the sleeve. An operation member is pivotably engaged with the opening and has a protrusion extending from an inside thereof. The outer tube includes a recessed area defined in an outer surface thereof and a hole is defined through a wall of the outer tube and located below the recessed area. The inner tube has a groove defined in an outer periphery thereof and a plurality of slots are defined through an inside of the groove. The protrusion is engaged with one of the slots of the inner tube. A width of the groove is wider than a width of the recessed area. A cover is pivotably connected to the sleeve and a spring is biased between the cover and an outside of the operation member.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.